Natural gas has been used as fuel for internal combustion engines in consist locomotives. Because natural gas has a lower volumetric energy density than traditional fuels, such as diesel and gasoline, the natural gas used by the locomotives is generally only practical to store in a liquefied state (“LNG”). At atmospheric pressures, the natural gas must be chilled to below about −160° C. to remain in liquid form. Consists having LNG-fueled locomotives store the LNG in insulated tank cars (a.k.a., tender cars) that are towed by the locomotive.
In order to be utilized as an effective engine fuel, liquefied natural gas requires more energy than a liquid counterpart to be stored, compressed, vaporized and transported within a train consist. This relatively greater amount of energy required to power ancillary equipment is typically drawn from the power output of the consist's main engine. The additional consumption of power results in undesirable consequences with regards to fuel and engine power efficiencies.
One method of improving fuel economy in a consist is described in U.S. Pat. No. 6,408,766 (“the '766 patent”) of McLaughlin that issued on Jun. 25, 2002. The '766 patent describes a tender car having the capacity to augment tractive forces of an associated locomotive on a consist by utilizing traction motors located onboard the tender car. The energy utilized to power the traction motors on a tender car is produced by the locomotive. By augmenting the propulsion of the locomotive, the tender car reduces the tractive load placed on the locomotive.
Although the system of the '766 patent may be capable of reducing the tractive load of a consist, it only provides benefit when the tender car is actively coupled with and being powered by the locomotive.
The tender car of the present disclosure solves one or more of the problems set forth above and/or other problems with existing technologies.